SPECIFIC AIMS / OBJECTIVES The imaging core will provide facilities for the application of fluorescent probes that permits estimation of dynamic changes in intracellular cations and membrane potential during cell activation with minimal disruption of the cellular function. The microscopic digital image analysis system is used for the measurement of ratio imaging and the system allows spatial and temporal resolution. The core provides specialized equipment, technical support and the expertise for the use of fluorescent probes in live cells and related cell biology techniques. The core will provide training and assistance in acquiring data using imaging techniques.